


Sensitivity

by sansos



Series: Daily Life of Dr. Kuroo [5]
Category: Haikyuu!!
Genre: Alternate Universe - After College/University, Alternate Universe - College/University, Domestic Fluff, F/M, One Shot, Pregnancy, Reader-Insert, So much science that it's probably just a textbook
Language: English
Status: Completed
Published: 2020-07-30
Updated: 2020-07-30
Packaged: 2021-03-05 22:48:12
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,609
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25613086
Author URL: https://archiveofourown.org/users/sansos/pseuds/sansos
Summary: In which you and Kuroo bicker about how to interpret a pregnancy test.
Relationships: Kuroo Tetsurou & Reader, Kuroo Tetsurou/Reader
Series: Daily Life of Dr. Kuroo [5]
Series URL: https://archiveofourown.org/series/1787737
Comments: 10
Kudos: 155





	Sensitivity

**Author's Note:**

> There is. So. Much. Science. I don’t even know what this is anymore. Kuroo x f!reader domestic fluff, mentions of way too much science probably. Seriously. This is your final warning. This is just science.
> 
> Just slipping a glossary here:   
> Diagnostic sensitivity refers to the ability of a test to identify true positive cases.   
> Diagnostic specificity refers to the ability of a test to identify true negative cases.

“Well?”

“Nope, nothing, nada,” you revealed as you showed Kuroo the plastic stick in your hand. A single blue line ran vertically across the length of the small plastic window, indicating that no, you were _not_ in fact pregnant.

“You’re sure that you’d be far enough along to have measurable levels of hCG in your bloodstream and urine?”

“Yes, I’ve been puking my guts out for the past two weeks, Tetsu. I’m pretty sure I’ve racked up enough of that hormone in my system by now if I was pregnant.”

He heaved a sigh as he ran a hand through his mop of black hair, racking through his head to think up possible explanations. It had to be that the test was wrong —there was no other way, he was so sure that you were pregnant. Leaving your inability to stomach anything aside, the increased urination, constant fatigue, and the sudden change in appetite… No, there _had_ to a logical explanation to explain why the test had come out negative.

“Um… How many replicates did you do?”

Your eyes narrowed, having taken offence at Kuroo’s remark. “Tetsu, _what_ do you even take me for?” you scowled. You turned around back to the sink and pulled out two more tests to show the man.

“ _Of course_ I did two more. All three replicates gave negatives.”

“What do the manufacturers say about the sensitivity then?” Kuroo asked after an uncomfortable silence, his lips drawn tight in a grimace. He had a couple of explanations for the discordance between your symptoms and the test results, but truthfully, this was _your_ area of expertise and he was really just drawing at straws at this point to prevent his hopes from being extinguished.

You frowned as you fumbled for the box, head jolting back ever so slightly when you looked at the number. “99%? That doesn’t sound right.”

Kuroo scoffed as he took the box in his hands and squinted at the fine print on the bag. “That’s a load of bull if you asked me,” he mumbled, returning the box back onto the counter. “If its sensitivity is 99%, I bet its specificity is 1%.”

You laughed as you gave your husband a light pat on the back. “You’re sounding rather bitter today.”

“Yeah, probably because I was all excited about being a dad… and you know, also since my job is literally to try and figure out how to lower the detection limit of antibody-based tests,” he grumbled as he took the stick back into his hand. “If you go around telling everyone that they’re pregnant regardless of if they are or aren’t, then of course your clinical sensitivity is going to be high. You’re going to capture everyone who is a true positive because _everyone_ is positive.”

“And all your true negative cases would end up misdiagnosed,” you agreed with a nod. “But regardless, they’re proven to work most of the time, and I got a negative, not a positive. It’s likely I’m just not pregnant.” You gestured again at the single line on the test.

“But hear me out,” Kuroo said, returning the plastic stick into your hands, “Hook effect.”

“And what about it?” You asked with a single raised eyebrow.

“What if you had so much hCG in your system that it oversaturated all potential binding sites on the test’s antibodies,” Kuroo suggested. “The hCG in the urine was never able to make it to the antibodies on the test line, therefore negative result?”

You shook your head, unconvinced by the suggestion. “Now why would I have overly saturated levels of hCG in the first place?”

Your husband shrugged, his lower lip sticking out in defeat with the cogs in his mind having finally grinded down to a halt.

“I’m just saying that if two PhDs can’t find a valid reason behind three consecutive negative results, it might just be because it’s a true negative. Maybe it’s just the stress inducing the vomiting and everything else.” You whispered gently as you placed your hand onto Kuroo’s neck. “We can always try again, Tetsu.”

“And I’m just saying that my gut says otherwise, and I’m sure your gut says so as well,” Kuroo replied, grabbing onto your hand and moving it up to his face to leave a kiss on your palm. He breathed another sigh as he wrapped his arms around your waist, resting his chin onto your head.

“You’re a clinician, you should know to let the symptoms guide you before a lab test,” Kuroo mumbled mindlessly while stroking your back as he held you in his arms. He paused for a second, a thought having sprung up into his mind. “But it wouldn’t hurt to measure the concentration directly instead of relying on a point-of-care test, right?”

You leaned back in Kuroo’s arms and stared at him, skepticism lining the edges of the tight lipped smile on your face. “Seriously?” you deadpanned.

Spinning you around and placing a hand on the small of your back, Kuroo lightly guided you towards the front door. “I’m a scientist. We always want to know our results with certainty,” he chirped happily as he looked down at your face with a wide grin. “You know that too, right? Or was your degree in chemistry—”

You slapped a hand over his mouth and glared at your other half. “If you try to convince me that biochemistry is better, I will kick you right here and right now.”

Kuroo simply shrugged as he draped your coat over your shoulders, pocketing the car keys by the door.

“OK, sure, whatever you say,” he laughed as he turned the door handle and ushered you through before following suit himself.

“Wouldn’t hurt to prove you wrong, I guess,” you snickered in response.

“Ain’t happening.”

“It’s happening.”

Kuroo looked at you from the driver’s seat, having slipped in and started the car during your exchange. He tilted his head over to the passenger seat to hurry you into the car, and with a roll of your eyes, you opened the car door and slid into the seat next to him.

Just as he was about to turn around to look out the rear window to back up the car, one arm on the wheel and the other draped across your seat, he stopped, looking at you with soft doe eyes and a matching goofy grin.

“Ain’t happening.”

—

“Guess congratulations are in order. Looks like you’re probably pregnant, (l/n)-san,” Shirabu said from his desk on his side of the office. You looked up from the case report you had been skimming over on your computer and walked over to your coworker’s side.

“Huh, hCG concentration’s outside of the point-of-care test’s reference range. No wonder it came back negative,” you mumbled to yourself as you looked over Shirabu’s shoulder. “Tetsu was right, huh, it _was_ the Hook.”

“It’s too early to tell, but elevated levels at this time by this amount could be because you’re carrying twins,” Shirabu suggested as he turned around to face you.

“We’ll have to wait for the ultrasound to be sure of it,” you agreed with a nod, having come to that conclusion yourself as well.

“Hmm? Twins?” Kuroo’s suddenly asked as he picked up the report in front of Shirabu, having somehow materialized into the room without anyone’s notice. He looked over at you, and then back to the results. “See, I told you that the test was wrong,” he puffed proudly as he handed the paper back to the blond. “Shall I enlighten you on the Hook effect again?”

Shirabu shot you a questioning look and you sighed with a shake of your head. “Don’t get him started,” you mumbled with an exasperated look on your face. “Spent the whole morning arguing with him about it.”

You turned back over to look at your husband. “How did you even get in here, normal visitors aren’t allowed into this wing.”

Kuroo pointed at Shirabu. “Hey, I’m here for Shirabu-sensei. We’re working on a manuscript together, right?” He winked, nudging at the man’s arm while Shirabu simply rolled his eyes in response, slightly peeved to have been dragged into your quarrel. Kuroo looked back at you in feigned surprise, bringing his hands up to his face. “It just so happens my beautiful wife’s in the office too! Wow, what a coincidence!”

You raised a hand up to your forehead to massage your temples as your other hand reached out to grab your embarrassment of a husband by the collar. “Shirabu-san, I’ll see you tomorrow,” you smiled with a small wave as you left the office, heading back into the long winded hallways of the department. Shirabu raised a hand in response, a light chuckle escaping his lips as he turned back around in his chair.

“Wait. (f/n), I’ve got a great idea,” Kuroo suddenly exclaimed in the middle of the quiet hallways of the hospital, gripping onto your wrist and pulling you lightly to get you to stop and turn around. “Hear me out. I have the _perfect_ names for our twins. How about B—”

“—If you name them Bio and Chem I will literally shave your head bald when you’re asleep,” you threatened with a dark look on your face, having interrupted your husband just before the word left his mouth.

“You love me too much to do that,” he teased as he pecked you on the cheek and tugged you along to keep walking. You simply groaned in reply.

To think that _one_ Kuroo was already this much of a hassle…

You weren’t sure what to expect with _three_.


End file.
